求助5年级maths题

sisisi

During a school year, a student was given an award of 25 c for each maths test he passed and was fined 50 c for each maths test he failed. At the end of the school year, the students had passed 7 times as many tests as he had failed, and received $3.75. How many tests did he fail?
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warmheart

7*x*0.25-x*0.5=3.75

x=3

cs_sos

为何x乘以0.5？

caicool

3 tests.

兵马俑

由于是50cents啊！

mjl

把Fail test 的次数设为X. 算式和二楼同样。

天天压马路

还有一题求解. 谢谢

  The XYZ club collected a total of $1.21 from its members with each member contributing the same amount . If each member paid for his or her share with 3coins,how many 5cent coins were contributed?

63848181

22，对吗？

sibada

不知道怎么做 ，标题问题有点confuse

新界一只牛

请问怎么做出22的？

信息量

谜底对吗？

ylxt

还没谜底，这是olympiad maths

michyy

十二1=十一x十一, 没有其余因数，只能是十一集体每人十一分。

koppera

十一分3个硬币，只能是5，5，1

dongsian

标题问题很老了，还有1分的。楼上正解。一共十一集体，22个5分的。

风中雨

还有一分的 ，谢谢，ls都白条，今天还。